Accessing Multiple List Elements by Index

Selecting specific elements from a list based on their index is a common operation in programming. In this question, a user seeks an optimal method to create a new list containing elements from a given list at predefined indices.

The user's approach of iterating through the indices and accessing each element individually is a straightforward solution. However, there are alternative approaches that can be more efficient or concise.

One alternative suggested is using the operator.itemgetter function. This function takes a set of indices as arguments and returns a callable object that can be applied to a list to retrieve the corresponding elements. For example:

from operator import itemgetter 
a = [-2, 1, 5, 3, 8, 5, 6]
b = [1, 2, 5]
print(itemgetter(*b)(a))
# Result: (1, 5, 5)

Another alternative involves using the NumPy library. NumPy provides powerful array operations, including the ability to access elements based on indices. This can be achieved using the a[b] syntax:

import numpy as np
a = np.array([-2, 1, 5, 3, 8, 5, 6])
b = [1, 2, 5]
print(list(a[b]))
# Result: [1, 5, 5]

It's worth noting that the user's current solution is also valid and reasonable. The choice between different methods depends on personal preferences and the specific context in which they are being used.